It is priorly known to provide a conduction path between two contact locations of which one is movable on a circular path, while the other is disposed stationary outside such circular path. Apparatus having such conductor paths include, for instance, cable coilers in which the electric cable or cord is wound on a reel. The cord can be pulled out of the housing of the apparatus. Under the action of a spring it is automatically rolled up again after a pulling force is removed. One essential problem here is the transfer of current from the firm attachment of the apparatus to the end of the line which is arranged turnably on the spool. This problem occurs in apparatus in which there are two contact locations which are movable relative to each other and one of which in most cases is developed as a fixed point. In addition to the above-mentioned cable winder, such an apparatus may also be an anti-rebound device for automotive vehicles in which the electric current feed is arranged in the steering wheel of an automobile.
For the transfer of current between contact locations which move relative to each other, wiper contacts or rings are priorly known. Such arrangements are subject to wear and are disadvantageous particularly in the case of low current intensities because of the higher transfer resistances.
U.S. Pat. No. 4,696,523, issued Sept. 29, 1987, is directed to a priorly known apparatus including a conductive path between two contact locations which are rotatable with respect to each other. In this apparatus, the conduction path is comprised of a flat ribbon cable wound in the manner of a coiled spring. Upon the rotation of one of the contact locations in one direction, the windings of such coiled spring are pulled together to reduce the diameter of the coiled spring, while rotation in the opposite direction causes the windings of such coil springs to expand and increase the diameter of the coiled spring. Accordingly, the relative movement of the two contact locations connected by such coiled spring results in a "breathing motion", similar to a watch spring. To protect against the considerable mechanical stress and kinking of the end portions of the flat ribbon cable firmly attached to the corresponding contact locations, such prior art apparatus includes strip-shaped stabilizers at each of the connections between the flat ribbon cable and the contact locations, each of such stabilizers being of dimensionally stable plastic and having a U-shaped cross section for closely enclosing the associated end portion of the flat ribbon cable.
U.S. Pat. No. 4,836,795, issued June 6, 1989, is directed to a priorly known apparatus for providing an electrical conduction path between a first contact location rotatable a plurality of rotations, in either direction, about a longitudinal axis, and a stationary contact location positioned radially from the rotatable contact location. Such apparatus is comprised of a bifilar spiral spring formed of a length of flat ribbon cable having at least two electrical conductors. The bifilar spiral coil spring is secured only by firmly attached connections at its opposite ends to the two contact locations; whereby it uncoils and slidably moves in response to the direction of rotation of the rotatable contact location, and upon reversal of such rotation, recovers its original shape and position between the two contact locations.